Atypical presentation of spine bone metastasis in prostate cancer mimicking Pott's disease

A 55-year-old man was hospitalized for a low back pain lasting for 3 months. Spinal MRI revealed a suggestive aspect of multilevel discitis L5-S1-S2 with paravertebral abscess. A thoraco-abdominal CT scan confirmed the presence of multiple pathological lymph nodes in several locations, bilateral micronodular pulmonary infiltrate; it also showed mirror bone erosions of vertebral L5 and S1 endplates, suggestive of disseminated tuberculosis with lung involvement and lymphadenopathy. A discovertebral L5-S1 biopsy was performed confirming the diagnosis of metastatic prostatic adenocarcinoma including a tumor infiltration of the intervertebral disc, without arguments for a septic processus superimposed without tuberculosis granuloma. Although rare, cases of metastases located at the disco-vertebral junction including prostatic cancer have already been described, and should be known to the clinician. The differential diagnosis with an infectious spondylodiscitis can be difficult in some case around the vertebral disc and in case of epiduritis and soft tissues involvement on MRI sequences. Disco-vertebral biopsy remains the cornerstone of the diagnosis.